PROS1 and thrombophilia: The impact of DOACs on laboratory assays used for thrombophilia testing (e.g., antithrombin, protein S, protein C, lupus anticoagulant, and activated protein-C resistance [APC-R]) is a well-known issue and may cause false-positive and -negative results.5, 6, 7, 8, 9Therefore, the correct interpretation of results that are performed in patient taking DOACs is mandatory to prevent misclassification and the subsequent clinical consequences.7